At least one inventive concept relates to semiconductor memory devices, and more particularly, to variable resistance memory devices and/or erase verifying methods thereof.
Demand for nonvolatile semiconductor memory devices capable of realizing high density and large capacity is gradually increasing. Accordingly, research is being conducted on nonvolatile random access elements having improved performance. For example, the nonvolatile random access elements may include a ferroelectric random access memory (FRAM) element using a ferroelectric capacitor, a magnetic RAM (MRAM) element using a tunneling magneto-resistive (TRM) film, a phase change memory element using chalcogenide alloys, a resistive RAM (RRAM) element using a variable resistance material film, and so on.
In the RRAM technology, memory characteristics such as high speed, large capacity, low power, and so on are possible. Thus, research for improving these memory characteristics is being conducted within the RRAM field. Variable resistance material films of RRAMs may show a reversible resistance variation according to a polarity or magnitude of an applied pulse. The variable resistance material films may include a CMR (Colossal Magneto-Resistive) material layer having a Perovskite structure or a metal oxide layer having conductive filament that is generated or dissipated by an electric pulse. A memory using a variable resistance material film including the RRAM may be referred to as a variable resistance memory.